Brush rigging



Nov. 21, 1961 MOORE ET AL 3,010,042

BRUSH RIGGING Filed May 21, 1959 INVENTORS.

2 Kenneth R. Moore Vear/ P. Hemmer, Jr: A Lawrence E. Julian L BY Robert J. fiche/fan Max 6. W/nfeman 3 J Y aRmaWL Their Attorney II/I/I/ .b

United States Patent 3,010,042 BRUSH RIGGING Kenneth R. Moore and Vearl P. Hexamer, Jr., Anderson,

and Lawrence E. Julian, Markleville, Max C. Whiteman, Anderson, and Robert J. Schelton, Markleville, Ind., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed May 21, 1959, Ser. No. 814,891 8 Claims. (Cl. 310-246) This invention relates to brush holders for dynamoelectric machines and more particularly to brush holder apparatus wherein a constant tension spring is used that maintains constant brush pressure during wearing of the brush.

In present day brush holder practice, it has become common practice to employ constant tension springs that include a self-rewinding volute. These brush holders have taken various designs and configurations and in general have been effective when used with constant tension springs, in providing uniform brush pressure during wearing of the brush.

It is an object of this invention to provide an improved brush holder that includes a constant tension spring for urging a brush into engagement with a commutator or the like and wherein the spring isattached to a support member to form a spring and support assembly that is easily fitted within the brush holder of this invention.

Still another object of this invention is to provide a brush holder assembly that includes a support member carrying a constant tension spring and wherein the support member engages shoulder means on a rigid brush holding member with the self-rewinding volute portion of the spring engaging one end of a brush. In accomplishing this object, the support member is held in tight engagement with the shoulder means as a result of the force exhibited by the spring, and it, therefore, is another object of this invention to provide a brush holder arrangement wherein the force exhibited by the constant tension spring is used to hold the spring and its support in place.

A further object ofthis invention is to provide a brush holder that includes a brush holdingmember formed of moldable insulating material that is fitted with a spring and support assembly comprised of a support member to which is attached the constant tension spring. In accomplishing this object, the brush holding member has integral shoulder means for engaging the support member to holdit in position.

Still another object of this invention is to provide a brush holder assembly that includes a brush holding member, to which is fitted a spring and support assembly including a support member and an attached constant tension spring, and wherein the brush holding member has ramp means for guiding the spring and support assembly into place and for aiding the holding of the spring and supportassembly in place once it has been moved to an assembled position- Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein preferred embodiments of the invention are clearly shown.

In the drawings:

FIGURE 1 is a sectional view of a part of a dynamoelectric machine that is fitted with the brush this invention.

FIGURE 2 is a view illustrating the various parts of the brush holder of this invention.

FIGURE 3 is a view similar to FIGURE 1 but illustrating the position of the spring and support assembly as it is being fitted to the brush holding member of the brush holder.

rigging of 3,010,042 Patented Nov. 21, 1961 Referring now to the drawings, and more particularly to FIGURE '1, a dynamoelectric machine is illustrated that is fitted with the brush holding arrangement of this invention. The dynamoelectric machine has a frame designated by reference numeral 10 and a commutator designated by reference numeral '12. It Will be appreciated that the brush holding arrangement of this invention could also be used with slip rings rather than with a commutator and it is, therefore, apparent that the commutator 12 could be any rotatable current conducting device. The frame 10 has an opening 14 which is closed by a cover member designated by reference numeral 16 and secured to the frame 10 by screws 18. When the cover is removed, the brush holding apparatus is accessible so that 'a new brush may be fitted to the dynamoelectric machine.

The brush holding arrangement of this invention includes a main brush holding member formed of moldable insulating material designated in its entirety by reference numeral 20. This brush holding member 20 has a brush holding chamber designated'by reference numeral 22 and is provided with a shoulder portion 24 that contacts the frame 10 of the dynamoelectric machine. The main brush holding member 20 is held fixed with respect to the frame 10 by the fastener designated by reference numeral 26. The main brush holding member 200i the brush holding assembly has another shoulder 28 that supports leads 30 and 3 2, the lead 32 being connected with a brush 34 that is disposed within the brush holding chamber 22. It is seen that the brush 34 has an inclined surface designated by reference numeral 36 and a second inclined surface 37 engaging the commutator 12.

The brush holding member 20- has a pair of ramp portions or ramps designated by reference numerals 38 and 40, each of which has an inclined surface 42. It is seen from FIGURES 1 and 2 that the ramp portions 38 and 40 are located adjacent one end of the main body portion 20 and extend from opposite side walls of the body portion 20. The brush holding member 20 also has a pair of lugs or lug members designated respectively by reference numerals 44 and 46. These lug members, as will become more readily apparent hereinafter, are adapted to engage a spring support for holding the spring support in position relative to the main brush holding member 20. In addition, the brush holding member 20 is formed with a sidewall 49 having guide means including two narrow ridges 47 that extend lengthwise of the holder and which contact one side of the brush 34. These ridges reduce the sliding friction between the brush and holder.

As noted hereinbefore, the brush holding member 20 is formed of moldable insulating material. When the brush holding member 20 is molded, the ramps 38 and 40, the ridges 47, the lugs 44 and 46, the screw holes and the brush holding chamber 22 are all formed together and the brush holding member 20 is ready for use. This greatly reduces the cost of fabrication of the brush holding assembly of this invention and provides an assembly that is comprised of a small number of parts that are easily assembled.

The brush holding arrangement of this invention includes a spring and support assembly generally designated by reference numeral 50 and including a main support member 52 and a constant tension spring 54. The constant tension spring 54 has a self-rewinding volute portion designated by reference numeral 56 and one end of the spring is riveted to the support member 52 as at 58. It is seen from FIGURE 2 that the support member 52 has cutaway portions defined in part by side edges 60 and 62.

When it is desired to fit a brush Within the main brush holding portion 20, the brush 34 is disposed within the brush holding opening 22' in such a position that the brush is between the ramps 38 and 40 and the ridges 47. The spring and support assembly 50 is then fitted into the brush holding chamber in a manner illustrated in FIGURE 3 with one end of the spring and support assembly being positioned between the ramps 38 and 40 and a side wall 63 of the brush holding member 20. In doing this, the self-rewinding volute portion 56 of the spring is caused to contact the upper inclined surface 36 of the brush. In addition, the side edges 60 and 62 defining part of the cutaway portions of the support member are positioned between and adjacent down-turned lugs 44 and 46. With brush in the position of FIGURE 3, the support member 52 is moved clockwise in FIGURE 3 to cause the portions 70 and 72 of the support member 52 to snap under the down-turned lugs 44 and 46. The final position of the brush is illustrated in FIGURE 1 and in this position the self-rewinding volute 56 constantly urges the brush 34 into engagement with the rotatable current conv ducting device 12.

It is seen from FIGURE 1 that the force exhibited by the constant tension spring 54 tends to move the support member 52 upwardly into tight engagement with the down turned lugs 44 and 46. Any tendency of the support member 52 to move clockwise in FIGURE 1 is arrested by the ramps 38 and 40. It will be appreciated that the ramps 38 and 40 also serve to guide the support member into a position where it is easily snapped under the lugs 44 and 46 as is evident from FIGURE 3.

When the brush is in its final assembled position, the side edges 60 and 62 of the support member 52 are positioned between lugs 44 and 46 while the lugs engage portions 70 and 72 of the support member 52. The distance between edges 60 and 62 is substantially equal to the distance between the inner edges of lugs 44 and 46. The distance between the side edges 74 and 76 of the support member 52 is substantially equal to the distance between the end walls 78 and 80 of the main brush holder portion 20. It thus is apparentthat the corners 39 of the ramps 38 and 40 will engage portions of the support member 52 when the support member is being fitted into the main brush holding member and will also serve to aid in holding the spring and support assembly in place once it has been fitted to the brush holding member 20.

Whiletheembodiments of the invention as herein disclosed constitute preferred forms, it is to-be understood that other forms might be adopted.

What isclaimed is as follows:

1. A brush holder assembly for a dynamo electric machine having arotatable-conductor means comprising, a brush holding member having a chamber, a brush positioned in said chamber having one end thereof engaging said rotatableconductor means, a brush spring and support assembly including a support member and a constant tension spring secured thereto, said spring having a portion secured to said support member adjacent one end thereof and including a self-rewinding volute, first and second laterally spaced lug members extending from said brush holding member into said chamber, said spring and support assembly being positioned within said chamber with flat surfaces of said support member engaging respective lug members and with said self-rewinding volute engaging the other end of said brush.

2. A brush holder assembly for a dynamo-electric machine having rotatable conductor means comprising, a brush holding member having a brush holding chamber, a brush positioned in said chamber having one end thereof engaging said rotatable conductor means, first and second laterally spaced lug members extending from said brush holdingmember into said brush holding chamber, said lug members being located adjacent the end of the chamber remote from said rotatable conductor means, a spring and support assembly including a support member engaging said lug means and further including a spring having a self-rewinding volute engaging an opposite end of said brush, said spring being attached to said support member adjacent the side that is immediately adjacent said rotatable conductor means.

3. A brush holder assembly for a dynamo-electric machine having rotatable conductor means comprising, a brush holding member formed .of moldable insulating material having a brush holding chamber extending therethrough, a brush positioned in said opening having one end thereof engaging said rotatable conductor, first and second laterally spaced lug members formed integrally with said brush holding member extending into said brush holding chamber, and means for urging said brush into engagement with said rotatable conductor, said last named means comprising a support member having flat surfaces engaging a respective lug member and carrying a constant tension spring having a self-rewinding volute portion that is in engagement with the end of the brush opposite from said rotatable conductor means, said spring being attached to said support member at a point adjacent said rotatable conductor means and urging said support member into tight engagement with said lug means.

4. A brush holder assembly for a dynamo-electric machine having rotatable conductor means comprising, a brush holding member having a chamber extending therethrough, a brush positioned in said chamber having one end thereof engaging said rotatable conductor, lug means extending from said brush holding. member, first and sec- 0nd ramp means having flat guide surfaces spaced from said lug means extending from said brush holding member into said brush holding chamber, and means for urging said brush into engagement with said rotatable con- :ductor, said last named means comprising a support .member'that is in engagement with said ramp means and said l-ug means and which carries a constant tension spring having a self-rewinding volute portion engaging-the end of said brush opposite from said rotatable conductor means.

5. A brush holder assembly for a dynamo-electric machine having rotatable conductor means comprising, amain brush holding member having a brush holding chamber, lug means extending from said brush holding member into said chamber, ramp means extending from said brush holding member into said chamber having flat guide surfaces angularly displaced with respect to the longitudinal axis of said brush holding chamber, a brush located within said chamber and positionedbetween said ramp means and one side wall of said brush holding. member,-said brush having one end thereof in engagement with said rotatable conductor means, and'meansfor urging said brush into engagement with said rotatableconductor means, said last named means comprising a support member that engages said lug means and said ramp means and which carries a constant tension spring having a self-rewinding volute engaging one end of said brush, said ramp means operating to guidesaid support member into place when said support member and'spring are fitted to said brush holdingmember.

6. A brush holding assembly for a dynamo-electric machine having rotatable conductor means comprising, a brush holding member having a brush holding chamber, ramp means extending fromfirst and second walls of said brush holding chamber each having an inclined -fiat surface facing a third wall of said brush holding member, first and second lug means extending from said third wall of said brush holding member into said chamber, first and second guide means extending from a fourth wall of said brush holding member, a brush positioned within said brush holding chamber and located between said guide means and one face of said ramp means, said brush engaging said rotatable conductor means, and means for urging said brush into engagement with said rotatable conductor means, said last named means comprising a support member that is engageable with both said lug means and said ramp means and which has attached thereto a spring having a self-rewinding volutethat is in engagement with one end of said brush, said ramp means serving 5 to guide said support member into position when said spring and support member are fitted to said brush holding member.

7. A brush holding assembly for a dynamoelectric machine having rotatable conductor means comprising, a brush holding member, first and second ramp members extending respectively from first and second walls of said brush holding member, first and second lug members extending from a third Wall of said brush holding member, first and second guide means extending from a fourth wall of said brush holding member, a brush positioned within said brush holding member and located between said guide means and said ramp members, said brush engaging said rotatable conductor means, and means for urging said brush into engagement with said rotatable conductor means, said last named means comprising a support member that is engageable with saidfirst and second lug members and with said ramp members, said support member carrying a spring having a self-rewinding volute that is in engagement with one end of said brush.

8. A brush holding assembly for a dynamoelectric machine having rotatable conductor means comprising, a brush holding member, first and second ramp members extending respectively from first and second walls of said brush holding member, first and second lug members extending from a third wall of said brush holding member, said ramp members being located between said lug members and said rotatable conductor means, a brush positioned within said brush holding member, and means for urging said brush into engagement with said rotatable conductor means, said last named means comprising a support member that is engageable with both lug members and with said ramp members and which has attached thereto a spring having a self-rewinding volute that is in engagement with one end of said brush.

References Cited in the file of this patent UNITED STATES PATENTS 2,602,100 McDonald July 1, 1952 2,802,960 Baker Aug. 13, 1957 2,840,733 Hanson June 24, 1958' 2,840,734 Nottelmann June 24, 1958 

